China's top disease control official has said the efficacy of the country's Covid vaccines is low, in a rare admission of weakness.
In a press conference, Gao Fu added that China was considering mixing vaccines as a way of boosting efficacy.
China has developed four different vaccines approved for public use, though some trials abroad had suggested efficacy as low as 50%.
Mr Gao later said his comments had been misinterpreted.
More than 100 million people in China have received at least one shot of the vaccine.
Beijing has insisted the jabs are effective and said in March that obtaining visas would be easier for foreigners who have received a Chinese vaccine.
What did Mr Gao say?
Gao Fu, head of the Chinese Centres for Disease Control and Prevention, on Saturday said at a conference the current vaccines "don't have very high rates of protection".
He suggested that the China was considering mixing Covid-19 vaccines, as a way of boosting efficacy.
Mr Gao explained that steps to "optimise" the vaccine process could include changing the number of doses and the length of time. He also suggested combining different vaccines for the immunisation process.
But he later appeared to backtrack on his comments, telling state media Global Times that "protection rates of all vaccines in the world are sometimes high, and sometimes low".
"How to improve their efficacy is a question that needs to be considered by scientists around the world," he told the paper.
He added that his earlier admission that Chinese vaccines had a low protection rate were a "complete misunderstanding".
Mr Gao's original and later comments have been largely unreported by Chinese media.
His original comments however, attracted some criticism on social media site Weibo, with commenters suggesting that he should "stop talking".
Source: BBC
